What’s the best free tool for competitor keyword research

General
1

I’m trying to grow a small website and really need to understand which keywords my competitors are ranking for, but my budget is basically zero. I’ve tried a couple of free trials from big SEO tools, but they either expired too fast or limited the data so much that I couldn’t get real insights. Can anyone recommend a genuinely useful free competitor keyword research tool, or a combo of free tools, that can help me uncover competitor keywords, search volume, and ranking difficulty without paying for a full subscription

2

Short answer with budget 0: use a mix of free data sources, not one “best” tool.

Here is a workflow that works well for small sites:

  1. Start with free Ahrefs tools
    • Ahrefs Free Webmaster Tools:

    • Verify your site.
    • Use Site Explorer for your own keywords and pages.
    • Check “Competing domains” to see who overlaps with you.
      • Ahrefs free “Site Explorer” demo:
    • Plug in 1 or 2 top competitors.
    • Export or copy the top organic keywords you see.
      Not full data, but enough to see patterns.

  2. Use Google itself as a keyword spy
    • Site: search

    • Search: site:competitor.com main keyword
    • Look at page titles and H1s, note repeating phrases.
      • Auto-suggest and People Also Ask
    • Type your seed keywords.
    • Copy suggestions and PAA questions into a sheet.
      • Related searches at bottom of SERP
    • Add those to your list.

  3. Free Similarweb version
    • Run competitor domains through Similarweb free.
    • Look at:

    • Top organic keywords.
    • Top pages by traffic.
      Data is rough, but helps for direction.

  4. SEO Minion or Detailed browser extensions
    • Use on competitor pages.
    • Extract titles, headings, meta descriptions.
    • Those hints show what they target.
    • Put those phrases into Google and see who ranks.

  5. Keyword Surfer extension
    • Gives rough volume inside Google search results.
    • Take keywords you stole from competitors and check:

    • Volume.
    • Similar keyword suggestions.

  6. Use Google Search Console for gaps
    • In GSC, export:

    • Queries where you are positions 5 to 20.
      • Search each query in Google.
      • Check who ranks above you.
      • Open their pages and note extra angles or subtopics they target.
      These are “near win” keywords where your content needs improvement.

  7. Build a simple sheet
    Columns:

    • Keyword
    • Source (Ahrefs demo, Google SERP, Similarweb, etc)
    • Competitor URL
    • Your current position
    • Search intent (info, commercial, etc)
    • Content idea / angle
      This helps you pick targets where:
      • Volume is ok.
      • Competition looks weak or outdated.
      • You already have some topical relevance.

  8. Focus on long tails
    You do not beat big sites on “best running shoes”.
    Go after things like:
    • “best running shoes for flat feet women overpronation”
    • “how to wash xyz product without shrinking”
    These come from:

    • People Also Ask.
    • “Related searches”.
    • Competitor blog subheadings.

If you want a single tool to start with, I would pick:
• Ahrefs Free Webmaster Tools for your site
• Keyword Surfer for quick SERP data
• Similarweb free for rough competitor keywords

Everything else comes from manual SERP digging and copying what works. It takes more time, but with no budget, time is the tradeoff.

3

If your budget is literally zero, I’d actually not chase more “tools” beyond what @shizuka already laid out. The bottleneck isn’t data, it’s focus.

Here’s a slightly different angle that leans more on strategy than on stacking more extensions:

  1. Use GSC as your main competitor tool
    People treat Search Console as “my keywords only,” but it’s secretly a competitor map:

    • Sort queries by impressions, filter positions 5–30.
    • For each query, open the live SERP.
    • Make a note of which sites keep showing up next to you across lots of queries.
      Those repeated domains are your real competitors, not whoever some tool decided.

  2. Steal topics, not just keywords
    Instead of obsessing over “what exact keywords do they rank for,” look at:

    • Their category structure and menu
    • Their “hub” / pillar pages
    • How they cluster content (series, guides, comparisons)
      Often one good content cluster beats 100 isolated long tails.

  3. Manually reverse engineer 3 to 5 “reference” competitors
    Pick a tiny set of competitors showing up over and over in the SERPs. For each:

    • Crawl their site with Screaming Frog free version (500 URLs is plenty for small sites).
    • Export titles, meta descriptions, H1s.
    • Sort by traffic potential keywords you recognize from the SERPs, not from some volume number.
      This is where I slightly disagree with heavy reliance on Similarweb: data’s often wildly off for small sites. Real SERP checks beat modeled traffic estimates.

  4. Forget volume, prioritize win potential
    For each potential keyword/topic, ask:

    • Can I make something 2x better or more specific than the current top 3?
    • Is at least one ranking page “weak” (thin, outdated, poor UX, generic)?
    • Does this keyword clearly match what I actually sell / do?
      If the answer is yes on all three, it’s worth targeting even if the supposed “volume” is tiny.

  5. Turn competitors into content prompts
    When you find a strong competitor article:

    • Scan comments (if blog / YouTube) for questions they didn’t answer.
    • Check “People Also Ask” around that exact page.
    • Look at internal links on that page for related topics they consider important.
      Those are often your easiest next posts and don’t need any extra tools at all.

  6. Reuse your own pages as “keyword magnets”
    Take a post that’s already getting impressions:

    • Expand it with FAQs that address People Also Ask and related queries.
    • Watch in GSC over 1–2 months as more long tails appear.
      You effectively turn Google itself into the keyword research tool, instead of trying to predict everything upfront.

If you insist on naming a single “best free tool”: I’d argue GSC + manual SERP checking beats any limited free third‑party tool. Everything else is just a convenience layer on top of what Google is already telling you.

4

If your budget is literally zero, I’d actually lean on “free ecosystems” rather than chasing a single magical free tool.

@shizuka already squeezed a lot out of GSC and manual SERP work, so here are different angles that complement that without repeating the same flow.

1. The closest thing to a “best free tool”: free tier stacks, not a single app

Individually, most free keyword tools are weak. Combined, they’re decent:

  • Google Ads Keyword Planner

    • Use it without running ads: plug in your competitors’ URLs under “Start with a website.”
    • Export ideas, then manually check which ones actually show your competitors in the live SERPs.
    • Pro: Real Google data, broad topic discovery.
    • Con: Volume is bucketed, intent is fuzzy, and it is skewed toward ad terms.

  • Ubersuggest free, Moz free, Similarweb free, etc.

    • Do not treat any one of them as “truth.”
    • Use them strictly to:
      • Find competitor domain lists
      • Get seed topics you then verify in SERPs
    • Pro: Quick way to surface topics you had not thought about.
    • Con: Data on small sites is often very wrong, like @shizuka hinted for Similarweb.

This is where a product title like “best free tool for competitor keyword research” actually needs translation: the “best” is usually the combo of Google’s own tools plus one or two free-layer suites, not a single brand.

2. Use Bing & YouTube as “shadow” competitor tools

Everyone stares at Google only. You can squeeze extra insight from places that are still search engines:

  • Bing SERPs

    • Search your main terms in Bing and see which sites keep appearing alongside you.
    • Often you will see smaller or niche sites that Google buries. They can give you:
      • Alternative angles for content
      • Less competitive phrasing / modifiers
    • Pro: Less noisy for small niches, different view on intent.
    • Con: You still need to verify everything on Google before you commit.

  • YouTube search

    • Search your topics and sort by “Most viewed.”
    • Look at:
      • Titles and thumbnails for phrase patterns
      • Comment questions that are not answered in the video
    • Turn those gaps into blog posts.
    • Pro: Uncovers problem language straight from users.
    • Con: Not all niches are active on YouTube, so can be a dead end.

3. Use “site:” and “intitle:” to reverse engineer competitor focus

You do not need paid keyword exports to map what a competitor is betting on.

Pick your top 3 competitors (that you found from GSC or SERPs, like @shizuka suggested) and in Google:

  • site:competitor.com intitle:'best'
  • site:competitor.com intitle:'vs'
  • site:competitor.com 'how to'
  • site:competitor.com 'review'

This gives you:

  • Their money pages (best, vs, review)
  • Their top-of-funnel tutorial content (how to)

You then:

  • List all topics where:
    • They have content
    • The current SERP shows at least one weak result
  • Ignore exact volumes. Prioritize:
    • Clear problem / product fit
    • Pages where you can be more specific or local

No third party tool, just advanced operators.

4. Copy their format, not just their keyword

This is where I politely disagree a bit with only thinking in terms of topics vs keywords.

You still want to notice format patterns:

  • Are “comparison tables” dominating your niche?
  • Are “X vs Y vs Z” posts ranking for tons of long tails?
  • Are checklists / templates driving links?

Free tools do not show you this. Manual pattern spotting does.

Workflow:

  1. Open top 10 results for a candidate topic.
  2. Note recurring patterns:
    • List posts with numbers
    • Very long guides
    • Tool comparisons
    • Short answers with strong FAQ schema
  3. If you see:
    • Everyone using one format
    • And one or two doing it obviously better
    • But still horrible UX or out of date
      Then you have a shot at outranking with the same format, cleaned up and refreshed.

5. Competitor internal links as keyword hints

Something that tends to be underrated:

  • Open one of your competitor’s bigger guides.
  • Scroll to the internal links sections:
    • “Related articles”
    • “You might also like”
    • In-content links they clearly want you to click

These are often their “priority topics” even if the pure volume is not huge.

You do not need a tool to:

  • List all those internal link anchor texts
  • Group them by theme
  • Turn each cluster into your own:
    • Hub page
    • Support articles

This aligns with @shizuka’s content cluster point but tags onto it a different signal: how they internally promote it.

6. When you actually should not chase more data

The biggest trap in “best free tool for competitor keyword research” threads is this mindset:

“If I just find the right tool, I can skip the hard work.”

Reality with a tiny site and zero budget:

  • You need a short list of topics you can absolutely crush.
  • You do not need perfect volume or perfect keyword lists.
  • You need clarity on:
    • What your user wants
    • What the current SERP fails at
    • Why your version deserves to exist

Extra tools give you more noise more than signal.

Pros & Cons of relying on a “best free tool for competitor keyword research” mindset

Pros

  • Forces you to:
    • Be resourceful with free stacks (GSC, Keyword Planner, free-tier suites)
    • Focus on strategy rather than shiny subscriptions
  • Keeps costs literally at zero while you test what content actually moves traffic and leads.

Cons

  • Free layers:
    • Rate limit you
    • Hide full data
    • Are often inaccurate for small sites
  • You will spend more time:
    • Manually checking SERPs
    • Copying ideas
    • Validating topics
  • At some point, once revenue allows, you will probably want at least one paid suite just to save time.

If you are absolutely forced to pick one “best free” approach:

  • Use GSC as your base
  • Add Google Ads Keyword Planner for some extra ideas
  • Layer manual SERP analysis + site: operators for competitor mining

Everything else is basically supporting cast.